ActionScript 2.0 Overview

Flash MX introduced components—ready-to-use interface widgets and code modules that implement commonly needed functionality. Flash’s built-in components make it relatively easy to create desktop-style Flash applications. Flash MX 2004 introduces the new v2 components, rewritten from scratch in ActionScript 2.0 and built atop version 2 of the Macromedia Component Architecture, which provides a much richer feature set than its predecessor. The new architecture necessitates new ways of developing and using components (see Chapter 12 for component usage). Officially, the v2 components require Flash Player 6.0.79.0 or higher; however, tests show that many v2 components work in earlier releases of Flash Player 6 (especially Flash Player 6.0.40.0 and higher). If you want to use a v2 component in a version prior to Flash Player 6.0.79.0, you should test your application extensively.

A single application produced in either Flash MX 2004 or Flash MX Professional 2004 can include both v2 components and Flash MX’s v1 components, provided the v1 components have been updated to support ActionScript 2.0 and the movie is exported in ActionScript 2.0 format.

Don’t confuse v1 and v2 components with the version of ActionScript in which they are written. Granted, v2 components are written in ActionScript 2.0 and there are no ActionScript 1.0 versions of the v2 components. However, although v1 components were written originally in ActionScript 1.0, versions updated to compile under ActionScript 2.0 are available.

Note: The v1 component update for ActionScript 2.0 is available at the Flash Exchange (http://www.macromedia.com/exchange/flash), in the User Interface category, under the title “Flash MX Components for Flash MX 2004.”

If nonupdated v1 components (i.e., those written in ActionScript 1.0) are used with v2 components in the same movie, some compile-time and runtime errors may occur, depending on the components used.

Note: Do not mix ActionScript 1.0 OOP techniques with ActionScript 2.0 code. If you are using classes, inheritance, and other OOP features, make sure all your code is upgraded to ActionScript 2.0.

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